British philosopher and economist John Stuart Mill (1806–73) is the author of several essays, including Utilitarianism (1863) - a defence of Jeremy Bentham's principle applied to the field of ethics - and The Subjection of Women (1869), which advocates legal equality between the sexes. This work, arguably his most famous contribution to political philosophy and theory, was first published in 1859, and remains a major influence upon contemporary liberal political thought. In it, Mill argues for a limitation of the power of government and society (democracy's 'tyranny of the majority') over the individual, and defines liberty as an absolute individual right. According to the still much debated 'harm principle', power against the individual can only be exercised to prevent harm to others. Full of contemporary relevance, this essay also defends freedom of speech as a necessary condition of social and intellectual progress.